The motor vehicle industry, particularly the passenger car and van portions of the industry, are increasingly relying on flush glass window mounting for improving the appearance of motor vehicles and reducing the aerodynamic drag of the vehicles to make them more fuel efficient. A number of conflicting requirements for such seals makes them difficult and expensive to produce and install. The increasingly complex shape of motor vehicle bodies requires seals that are not simply bent in a plane to surround the top edge of a flat glass window. The seals are formed not only at the radii (corners of the glass) but are also arched vertically to coincide with the curved top surface of the glass and rounded sides of the automobile.
Heretofore, thermosetting materials such as ethylene-propylene-diene-monomer rubber (EPDM) have been used extensively for vehicle window seals. Some complex seals have included portions formed from other materials such as thermoplastic materials, but EPDM has usually been a major portion of the seal. EPDM has a number of characteristics that make it useful for forming window seals. It is relatively inexpensive, effective, easy to extrude, and has outstanding weatherability, resilience, resistance to abrasion, and durability. However, it has several disadvantages that make it increasingly hard to adapt to the ever more stringent requirements of the motor vehicle industry. Not the least of these disadvantages is that EPDM is normally made black. Second, in order to form EPDM into the complex shapes required by the motor vehicle industry, it is often necessary to provide separately manufactured molded corner pieces, and frequently a wire carrier, a stamped metal carrier or a solid metal support. Each of these adds to the cost of the seal.
To improve the appearance of motor vehicles, the industry demands window seals that are colored to enhance the appearance of the vehicle, usually by matching the body color. Obtaining a color on EPDM has been less than satisfactory in the past, whereas thermoplastics are readily colored.
Although EPDM is cost effective (inexpensive) as a material, the total cost of making and installing an EPDM seal on a motor vehicle is high. The seal must not only be formed at the radii of the glass by cutting, mitering or welding molded pieces, but it must also be arched in the vertical direction to coincide with the curved glass and rounded sides of the vehicle. To accomplish this with EPDM, a .metal support internal to the EPDM is added, usually as the EPDM seal is extruded. Massive and expensive roll forming machinery and tooling and stretch bending equipment and tooling are required to form the extruded seal to the desired configuration in three dimensions. Thus, the total cost, that is the cost of the seal and the capital cost of equipment needed to form it, is high.
It is an object of this invention to provide an improved vehicle window glass seal that overcomes the disadvantages of known seals. The seal of the invention comprises two members, a substantially rigid first carrier member thermally formed from a hard, rigid or semi-rigid plastic and a soft plastic, and a second sealing member made from resilient material, preferably rubber. More particularly, it is an object of the invention to provide a seal in which the first member comprises a dual durometer, thermoplastic elastomer (TPE) which attaches to a vehicle body and can be color matched to an automobile and which can be thermally formed to match the contour of the vehicle, thus eliminating the need for the expensive, massive, roll forming machinery and tooling and stretch bending equipment and tooling mentioned before.
The first member can be thermally formed by extrusion or molding in one piece and conformed to the contour of the vehicle opening. Thus molded joint lines and the need for cutting, mitering or welding of the carrier member to fit the corners are avoided. The second member can be formed by extrusion of a one-piece, relatively flat rubber member which can be readily provided with a sliding surface, such as a slip coating or flocking.
The seal of the present invention has other advantages. The carder member formed from substantially rigid thermoplastic material does not require a wire carrier, a stamped metal carrier or a solid metal support and can be provided with a finish gloss as high as 60 compared to rubber which is usually limited to a 20 gloss or less. The assembly requires less labor and capital expenditures not only to produce, but to install. The completed assembly is lighter than the all-rubber assemblies used in the past. Overall, the seal of this invention is less expensive than known seals and is more versatile, more attractive, and easier to maintain.